Optical brightening agents with high whitening power their manufacture and use

ABSTRACT

B-FORM CRYSTALS OF A COMPOUND REPRESENTED BY THE FORMULA   (R-PHENYLENE-NH-(6-MORPHOLINO-S-TRIAZIN-2,4-YLENE)-NH-   (3-(M-O3S-)-1,4-PHENYLENE)-CH=)2   WHEREIN R IS HYDROGEN ATOM OR METHYL GROUP; AND M IS SODIUM OR POTASSIUM HAVING A PARTICLE SIZE OF ABOUT 1X2U WHICH IS PREPARED BY PULVERIZING SAID CRYSTALS IN THE PRESENCE OF ALKALINE PHOSPHATES AND/OR ALKALINE SILICATES OR IN THE PRESENCE OF ALCOHOL, ESTER, KETONE, HYDROCARBON OR A MIXTURE THEREOF.

United States Patent Oflice U.S. Cl. 252-3013 W 14 Claims ABSTRACT OFTHE DISCLOSURE B-Form crystals of a compound represented by the formulawherein R is hydrogen atom or methyl group; and M is sodium or potassiumhaving a particle size of about 1X2 which is prepared by pulverizingsaid crystals in the presence of alkaline phosphates and/or alkalinesilicates or in the presence of alcohol, ester, ketone, hydrocarbon or amixture thereof.

This invention relates to pulverized optical brightening agent and to aprocess for preparing the same. More particularly, the inventionpertains to pulverized fi-form crystals of the compound having theformula shown below and to a process for the production thereof,

R N N I H O C H2 wherein R is hydrogen atom or methyl group; and M issodium or potassium.

The compounds represented by the above-mentioned formula have been knownas optical brightening agents for blending with detergents. Ordinarily,they are classified into two kinds of compounds different in crystalform; compounds in the form of yellow wfOIIIl crystals (here inafterreferred to as ct-form) and compounds in the form of white p-formcrystals (hereinafter referred to as .B-forrn), Compounds obtainedaccording to ordinary synthesis reactions are of the yellow wform. Whensubjected to X-ray analysis, u-form compounds of the aforesaid formula,wherein R is hydrogen atom, for example, show sharp diffraction peaks at26 of 50, 9.0, 15.0", 21.0 and 26.0". On the other hand, compounds ofthe fl-form are' obtained by subjecting said a-form compounds to containtreatment (on- 13 transition), e.g. the treatment disclosed in BelgianPat. 680,847. They are white 3,630,944 Patented Dec. 28, 1971 inappearance and are columnar crystals large in grain size ranging fromabout 3x20 to 1 mm. x 8 mm. In the case of fi-form compounds of theaforesaid formula, wherein R is hydrogen atom, for example, there areobserved, according to X-ray analysis, markedly sharp diffraction peaksat 20 of 3.2, 8.8, 9.5", 10.4, l6.4, 18.4, 20.2, 21.4 and 25.3".

Compounds which are actually employed, are those of said fi-form. Theyare useful as optical brightening agents for cellulosic materials andparticularly display such markedly excellent efficiencies as shown belowwhen used as optical brightening agent for detergents.

(1) They are excellent in optical brightening efficiency on fabrics.

(2) They are prominent in chlorine bleach fastness and light fas'tness.

(3) They are excellent in optical brightening efficiency on appearanceof detergents.

Despite such excellent efficiencies as mentioned above, however, the,B-form compounds are extremely unstable.

Accordingly, when allowed to stand in the presence of water, forexample, they are immediately brought back to the original a-forrn (B-0: transistion). The compounds, which have once been converted to thea-form, do not become white unless they are subjected to the aforesaida- ,B transition treatment. Moreover, in using said [3- form compoundsin admixture with a detergent, the said compounds are ordinarilysupplied in the form of an aqueous dispersion, suspension or solution,and are frequently allowed to stand as a stock solution for a relativelylong period of time. In such a case, the stock solution is naturallycolored to yellow.

For the prevention of such coloration, there has conventionally beenadopted a procedure to use the stock solution immediately afterpreparation. Such a procedure, however, greatly deteriorates theoperability.

Further, in using the above-mentioned fl-form compounds in admixturewith a detergent, it is necessary that said compounds be pulverized asfine as possible in order that said compounds effectively deposit on afabric or the like to impart optical brightness thereto. This kind ofdye is difficultly water-soluble, and therefore it is desired thatparticles of the dye be made fine to improve the water-solubilitythereof and to increase the brightening effect thereof, particularly atlow temperatures, on a fabric or the like.

For pulverization of such ,H-form compounds, there may be adopted amechanical procedure using a ball mill or the Jet Mizer manufactured byFluid Energy Processing & Equipment Co. However, according to the ballmill procedure, the pulverizing operation is inefficient, whileaccording to the latter procedure, there is a limit in degree ofpulverization (particles having a granularity of about 3 10 areordinarily obtained). Further, there may be adopted a process in whichthe }3-fOIIIl compounds are pulverized in an aqueous medium in such amanner, for example, that an aqueous suspension of the compounds ismixed under vigorous agitation with glass beads to pulverize thecompounds (hereinafter referred to as the glass beads pulverizationprocess) or the suspension is subjected to a ball mill process.According to the abovementioned processes, it is possible to easilyobtain dye particles having a size of about 1X2 However, when subjectedto said processes of pulverization in water, the White fl-forrncompounds are changed in color to yellow to green in several minutesafter initiation of the operation and are converted to the aforesaida-form. This indicates the fact that in an aqueous medium, the p-aatransition of crystals takes place quite easily. Moreover, suchtransition cannot be inhibited by addition of a common inorganic salt orsurface active agent. When the crystals, which have been greatly coloredto yellow to green, are blended with a detergent, the color of thedetergent is markedly yellowed and the commodity value thereof isgreatly reduced.

An object of the present invention is to provide pulverized opticalbrightening agent of ,B-form compounds represented by the aforesaidformula, which compounds are prevented from fi-m transition and do notcause yellowing.

Another object is to provide washing agents containing pulverizedfl-form compounds of the aforesaid formula.

A further object is to provide optical brightening agents excellent inbrightening efficiency at low temperatures.

A still further object is to provide a process for preparing such stable[i-form compounds as mentioned above which are prevented from +0:transition and are fine.

The present invention will be explained in detail below.

(A) Crystal pulverization process The crystal pulverization process iscarried out in the following manners:

The S-form compounds represented by the aforesaid formula are mixed withalkaline phosphates and/or alkaline silicates and water, the amount ofthe compound being 0.1-0.5 time the weight based on the total weight ofthe phosphates and/or silicates and water, and the amount of thephosphates and/or silicates being 0.050.5 time the weight based onwater. The mixture is subjected to glass beads pulverization process, orto ball mill or sand mill process and is treated until the particle sizeof said compound becomes about 1 2a under microscopic observation.During the treatment, the mixture is desirably heated to to 100 C. Ifnecessary, the mixture may be incorporated with third materials, e.g.and +5 transition promoter such as i-butanol, methyl Cellosolve ormethyl carbitol; a nonionic surface active agent; and a neutral or basicinorganic salt such as Glaubers salt, sodium chloride, sodium hydroxideor sodium carbonate.

The resulting liquid may be directly added to a detergent. If necessary,however, the liquid can be formed into a powder through such drying stepas spray drying, oridinary heat drying or the like.

The alkaline phosphates employed in the present invention include sodiumorthophosphate, potassium orthophosphate, sodium pyrophosphate,potassium pyrophosphate, sodium tripolyphosphate and potassiumtripolyphosphate; alkaline phosphates which, when formed into aqueoussolutions, come to show a pH of at least 8; and aqueous solutions oforthophosphoric acid, metaphosphoric acid, pyrophosphoric acid,tripolyphosphoric acid, sodium primary phosphate, potassium primaryphosphate, sodium secondary phosphate, potassium secondary phosphate,sodium metaphosphate and potassium metaphosphate which have been madealkaline by addition of an alkaline substance, e.g. caustic alkali oralkali carbonate.

The alkaline silicate employed in the present invention include sodiumsilicate, potassium silicate, sodium tetrasilicate, potassiumtetrasilicate, sodium metasilicate and potassium metasilicate; andaqueous solutions of silicon monoxide, silicic acid, tetrasilicic acidand metasilicic acid which have been made alkaline by addition ofalkaline substances, e.g. caustic alkali and alkali carbonate.

An organic solvent may be used in place of alkaline phosphates and/oralkaline silicates in the aforesaid pulverization process, wherebyfl-form crystals of the compounds represented by the aforesaid formulacan be fine- 1y pulverized without yellowing (without causing 5+transition). For this purpose, the use of alcohols, esters, ketones,hydrocarbons, halogenated hydrocarbon and mixed solvents thereof, whichdo not substantially dissolve the above compounds, is extremelyeffective.

The alcohols employed in the present invention include aliphaticalcohols such as methanol, ethanol, n-propanol, i-butanol andcyclohexanol; the esters include aliphatic esters such as methylacetate, ethyl acetate and methyl propionate, and aromatic ester such asethyl benzoate and the like; the ketone include aliphatic ketones suchas acetone, methylethylketone and methyl-i-butylketone, and aromaticketones such as acetophenone and benzophenone; and the hydrocarbonincludes liquid aliphatic hydrocarbons such as pentane, n-hexane andcyclohexane, halogenated aliphatic hydrocarbons such as chloroform,carbon tetrachloride, dichloroethane, trichloroethane, dichloroethyleneand trichloroethylene, aromatic hydrocarbons such as benzene, tolueneand xylene, and halogenated aromatic hydrocarbons such asmonochlorobenzene and dichlorobenzene.

These organic solvents may be used in the form of mixtures of 2 or more.

fl-Form crystals of the compounds of the aforesaid formula are suspendedin an amount of 0.l0.5 time based on the weight of the said solvent andare pulverized according to glass beads pulverization process or to ballmill or sand mill mill process until the crystals come to have aparticle size of about IXZp. under microscopic observation. Theresulting liquid can be directly incorporated into a detergent. Ifnecessary, however, the liquid may be formed into a white pulverizedpowder either by removing the organic solvent by distillation underreduced pressure or at atmospheric pressure, or by separating the solidsfrom the organic solvent by filtration or centrifuge.

(B) Washing agent containing the pulverized fl-form compounds A solutionor suspension of a soap or a synthetic detergent is homogeneously mixedwith the liquid or powder obtained by the above process (A), and thenthe mixture is dried and pulverized. When said liquid or powder isblended in an amount of about 0.01 to about 10% by weight based on thedry detergent, a marked improvement in appearance of the detergent isobserved.

The liquid or powder obtained according to the above process (A) may notonly be mixed directly with a detergent but may also be blended with adetergent solution or suspension containing a suitable builder such asGlaubers salt, phosphate, benezne type sulfonate, soda ash or CMC.Alternatively, said liquid or powder may be mixed with the builder afterblending the same with a detergent. After the mixing, the mixture may bedried according to any of hot air drying, vacuum drying at normaltemperature or spray drying. In the case of soaps composed mainly ofhigher fatty acids, they are homogeneously mixed with said liquid orpowder and are then cooled and dried to obtain desired products.

The soaps referred to herein include Marseille soaps, and the syntheticdetergents include alkylbenzenesulfonate type detergents such as sodiumdodecylbenzenesulfonate; a-olefin type detergents such as sodiuma-olefin sulfonate; and aliphatic alcohol type detergents such as sodiumlauryl alcohol sulfate.

(C) Compositions The fl-form compounds are mixed according to theconventional mixing procedure with alkaline phosphates and/or alkalinesilicates to obtain a solid composition, the amount ratio of thecompound and the phosphates and/or silicates being 110.1 to 10.

In this process, if necessary, water is employed to form liquidcompositions such as aqueous dispersion and aqueous suspension. Opticalbrightening composition in solid state incorporated with alkalinephosphates and/or alkaline silicates does not suffer from yellowing atall even when they are formed into such aqueous dispersions, suspensionsor solutions as mentioned above. Further, they are markedly stable ascompared with dye compositions incorporated or not incorporated withother salts. This indicates in the fact that the above-mentioned saltsact as markedly strong ,B-Mx transition-preventing agents. The alkalinephosphates and alkaline silicates employed may be the same as mentionedin item (A).

The present invention will be illustrated below with reference toexamples, but the scope of the invention is not limited to theseexamples. Parts are by weight.

10 parts of fl-form crystals of a compound represented by the aboveformula were added to 100 parts of a 10% aqueous sodium tripolyphosphatesolution. To this mixture were added 200 parts of glass beads, and theresulting mixture was stirred at 70-80 C. for 2 hours to finelypulverize said crystals. Thereafter, the mixture was passed through a100 mesh wire net to remove the glass beads, and the resulting liquidwas subjected to spray drying to obtain a pure white dye powder (fi-formcrystals having particle size of about 1X2 This dye powder (dye content:0.6 part) was thoroughly kneaded with 10 parts of 1 N-caustic soda andwas then charged with 150 parts of water. Subsequently, the mixture wasstirred at 40 C. to form a dispersion. To this dispersion was added 200parts of an international heavy duty detergent (60% sodiumdodecylbenzenesulfonate:sodium tripolyphosphate:Glaubers salt=l:1:1),and the mixture was kneaded at 40 C. for minutes. Thereafter, themixture was pre-dried at 90 C. for 2 hours and was then dried at 110 C.for 6 hours. The dried mixture was pulverized and was passed through a35 mesh wire net to obtain a washing agent.

The thus obtained washing agent was markedly excellent, as shown below,in optical brightening efficiency at low temperatures and appearance ofwashing agent as compared with a washing agent prepared in the samemanner as above except that a dye powder obtained through Jet Mizerpulverization was used.

Optical brightening efliciency on cotton parts of ,B-form crystals ofthe dye (potassium salt) employed in Example 1 were added to 100 partsof a 5% aqueous potassium tripolyphosphate solution. To this mixturewere added 3 parts of potassium carbonate and 200 parts of glass beads,and the resulting mixture was stirred at room temperature for 2 hours tofinely pulverize crystals. Thereafter, the mixture was treated in thesame manner as in Example 1, to obtain a white dye powder (ti-formcrystals having particle size of about l 2,u).

The washing agent prepared by incorporation of said dye powder showedmarkedly excellent properties like in the case of the product obtainedin Example 1.

EXAMPLE 3 20 parts of ,B-form crystals of the dye employed in Example 1were added to 100 parts of a 10% aqueous sodium orthophosphate solution.To this mixture were added 2 parts of i-butanol and 250 parts of glassbeads, and the resulting mixture was stirred at 7080 C. for 4 hours tofinely pulverize crystals. Thereafter, the mixture was treated in thesame manner as in Example 1,

to obtain a pure white dye powder (ti-form crystals having particle sizeof about 1 2,u).

The washing agent prepared by incorporation of said dye powder showedmarkedly excellent properties like in the case of the product obtainedin Example 1.

EXAMPLE 4 Example 3 was repeated, except that a nonionic surface activeagent, e.g. sulfonated naphthalene-formaldehyde condensation product wasused in place of i-butanol, whereby the same results as in Example 3were obtained.

EXAMPLE 5 Cfiz CH2 JJHZ H2 \O 2 (II fl-Form crystals of a compoundrepresented by the above formula were treated in the same manner as inExample 2, except that sodium pyrophosphate was used in place of thepotassium tripolyphosphate, whereby a dye powder excellent in propertieslike in the case of the product of Example 1 was obtained.

EXAMPLE 6 SO Na (III) fl-Form crystals of a compound represented by theabove formula were treated in the same manner as in Example 2, exceptthat sodium primary phosphate was used in place of the potassiumtripolyphosphate, whereby a dye powder excellent in properties like inthe case of the product of Example 1 was obtained.

EXAMPLE 7 The liquids of Examples 1 and 5 were directly blended withdetergents without adopting the drying step, whereby washing agentsmarkedly excellent in properties like in the case of the products ofExamples 1 and 5 were obtained.

EXAMPLE 8 The liquid composition of Example 1 was subjected to a ballmill at room temperature and was then spray-dried, whereby a dye powderexcellent in properties like in the case of the product of Example 1 wasobtained.

EXAMPLE 9 To a mixture comprising 10 parts of B-fOrm crystals of thecompound represented by the Formula I and parts of i-butanol were added200 parts of glass beads, and the mixture was stirred at roomtemperature for 2 hours to finely pulverize crystals. Subsequently, themixture was passed through a 100 mesh wire net to remove the glassbeads, whereby a liquid ([i-form crystals having particle size of about1X2,u) was obtained. The washing agent prepared by incorporation of thethus obtained dye liquid displayed markedly excellent efficiencies likein the case of the product obtained in Example 1.

7 EXAMPLE 10 To a mixture comprising parts of fi-form crystals of thedye employed in Example 9 and 100 parts of methyl acetate were added 250parts of glass beads, and the mixture was stirred at room temperaturefor 4 hours to finely pulverize crystals. Subsequently, the glass beadswere removed by the same manner as in Example 9 to obtain a liquidcontaining fl-form crystals having particle size of about 1 2 t.

The washing agent prepared by incorporation of the obtained dye liquiddisplayed markedly excellent efficiencies like in the case of theproduct obtained in Example 1.

EXAMPLE 11 Example 10 was repeated, except that ethyl benzoate was usedin place of methyl acetate, to obtain the same result as in Example 10.

EXAMPLE 12 To a mixture comprising 10 parts of fl-form crystals of thedye (potassium salt) employed in Example 9 and 100 parts of acetone wereadded 200 parts of glass beads, and the mixture was stirred at roomtemperature for 2 hours to finely pulverize crystals. Subsequently, theacetone was removed under reduced pressure to obtain a white dye powder(B-form crystals having particle size of about 1X2 The washing agentprepared by incorporation of the thus obtained dye powder displayedmarkedly excellent efficiencies like in the case of the product obtainedin Example 9.

EXAMPLE 13 Example 12 was repeated, except that acetophenone was used inplace of acetone and filtration was effected in place of the reducedpressure distillation, to obtain the same result as in Example 12.

EXAMPLE 14 B-Form crystals of the compound represented by the Formula IIwere treated in the same manner as in Example 9, except that n-hexanewas used in place of ibutanol, to obtain a liquid having excellentefficiencies like in the case of the product of Example 9.

EXAMPLE l5 fi-Form crystals of the compound represented by the FormulaIII was treated in the same manner as in Example 9, except thattrichloroethylene was used in place of i-butanol. Thereafter, thetrichloroethylene was removed under reduced pressure to obtain a paleyellowish white dye powder.

The washing agent prepared by incorporation of the thus obtained dyepowder displayed excellent efficiencies like in the case of the productobtained in Example 9.

EXAMPLE 16 fl-Form crystals of the compound employed in Example 14 weretreated in the same manner as in Example 9, except that benzene was usedin place of i-butanol. Thereafter, benzene was removed under reducedpressure to obtain a white dye powder.

The washing agent prepared by incorporation of the thus obtained dyepowder displayed excellent eificiencies like in the case of the productobtained in Example 9.

EXAMPLE 17 Example 16 was repeated, except that monochlorobenzene wasused in place of benzene and filtration was eifected in place of thereduced pressure distillation, to obtain the same result as in Example16.

EXAMPLE l8 fl-Form crystals of the dye (potassium salt) employed inExample 9 were treated in the same manner as in 8 Example 9, except thata mixed solvent comprising methanol and benzene in a volume ratio of 1:1was used in place of i-butanol. Thereafter, the solvent was removed bynormal pressure distillation to obtain a white dye powder S-formcrystals having particle size of about 1 2/ The washing agent preparedby incorporation of the thus obtained dye powder displayed markedlyexcellent efiiciencies like in the case of the product obtained inExample 9.

EXAMPLE 19 The liquid composition of Example 9 was subjected to the ballmill pulverizing process at room temperature and was then centrifuged toseparate solids. The separated solids were directly added to adetergent, whereby the washing agent displayed excellent efliciencieslike in the case of the product obtained in Example 9.

EXAMPLE 20 Example 9 was repeated, except that fi-form crystals of acompound represented by the above formula was used, whereby a liquid(containing fi-form particles having a size of about 1+2 was obtained.

EXAMPLE 21 The dye powder (dye content: 0.6 part) obtained in Example 1was thoroughly kneaded with 10 parts of l N-caustic soda and was thencharged with 150 parts of water. Subsequently, the mixture was stirredat 40 C. to form a dispersion. To this dispersion was added 200 parts ofan international heavy duty detergent (60% sodiumdodecylbenzenesulfonate sodium tripolyphosphate: Glaubers salt lzlzl,and the mixture was kneaded at 40 C. for 5 minutes. Thereafter, themixture was predried at C. for 2 hours and was then dried at 110 C. for6 hours. The dried mixture was pulverized and was passed through a 35mesh wire net to obtain a washmg agent.

EXAMPLE 22 The powder (dye content: 0.5 part) obtained in Example 5 wasdispersed in 5 parts of hot water and was added to an aqueous suspensioncomprising 30 parts of water and parts of sodium a-olefin sulfonatehaving 15-18 carbon atoms. Subsequently, the dispersion washomogeneously stirred and was then spray-dried to obtain a washingagent.

EXAMPLE 23 The liquid obtained in Example 20 was treated in the samemanner as in Example 21, whereby the washing agent was obtained.

EXAMPLE 24 The powder obtained in Example 15 was treated in the samemanner as in Example 22, whereby a washing agent was obtained.

EXAMPLE 25 10 parts of ,B-form crystals of the compound represented bythe Formula I were mixed with 5 parts of sodium tripolyphosphate toprepare a composition. This composition did not become yellow at alleven when formed into a stock solution by dilution with 50 parts ofwater.

9 EXAMPLE 26 To a mixture comprising 10 parts of fi-form crystals of acompound represented by the Formula II and 2 parts of sodiumtripolyphosphate was added 100 parts of Water to prepare awater-dispersed composition. This composition was stable as comparedwith compositions incorporated or not incorporated with other salts andshowed no yellowing at all.

EXAMPLE 27 Compositions were prepared according to the prescriptions setforth in the following table:

Part Part of of the the Part B-form com- Alkaline phosof compound poundphosphate phate Property water (I) 10 Potassium tri- 2 Liquid 100polyphosphate. (I) 10 Sodium ortho- 3 Solid phosphate. (1).. 10 Sodiummeta- 2 do 0 phosphate. (II) 10 Sodium pyro- 1 Liquid 100 phosphate.Sodium primary (IV) 10 phosphate. 2 Solid O Caustic soda 3 Potagsiumslec- 1 d on aryp os- 0 0 (III) 10 pham Soda ash 2 All of theabove-mentioned compositions were extremely stable, and stock solutionsformed therefrom showed no yellowing even when allowed to stand for amonth.

EXAMPLE 2-8 10 parts of fi-form crystals of the same compound as inExample 25 were mixed with 5 parts of sodium silicate to prepare acomposition. This composition showed no yellowing at all even whenformed into a stock solution by dilution with 50 parts of water.

EXAMPLE 29 Compositions were prepared according to the prescriptions setforth in the following table:

Part of Part of the the B-fonn comsili- Part of compound pound Alkalinecate Property water Compound:

(1) a; {Sihcicacrd g }Liquid 100 (H) {caustic soda 2 100 (IV) 10 Sodium5 Solid o metasilicate.

(III) 10 Potassium 5 do 0 tetrasilicate.

All of the above-mentioned compositions were extremely stable, and stocksolutions formed therefrom showed no yellowing even when allowed tostand for a month.

What we claim is:

1. A process for pulverizing an optical brightening agent, characterizedin that fi-form crystals of a compound represented by the formula,

10 wherein R is hydrogen atom or methyl group; and M is sodium orpotassium, are pulverized to a particle size of about 1 2 in thepresence of:

(a) a mixture of alkaline phosphates and water, a mixture of alkalinesilicates and water or a mixture of alkaline phosphates, alkalinesilicates and water, the amount of the compound being 0.1-0.5 times theweight of the mixture, and the amount of the alkaline phosphates, thealkaline silicates or the mixture thereof being 0.05-05 times theweight. of the water; or

(b) in the presence of at least one solvent selected from the groupconsisting of alcohols, esters, ketones halogenated hydrocarbons andhydrocarbons, the amount of the compound being 0.1-0.5 times the Weightof the solvent.

2. A process according to claim 1, wherein the p-form crystals arepulverized in the presence of the mixture of an tat- 5 transitionpromotor selected from the group consisting of i-butanol, methylCellosolve and methyl Carbitol; a nonionic surface active agent; and aneutral or basic inorganic salt selected from the group consisting ofGlaubers salt, sodium chloride, sodium hydroxide and sodium carbonate.

3. A process according to claim 1, wherein the alcohol is one memberselected from the group consisting of methanol, ethanol, n-propanol,i-butanol and cyclohexanol.

4. A process according to claim 1, wherein the ester is one memberselected from the group consisting of methyl acetate, ethyl acetate,methyl propionate and ethyl benzoate.

5-. A process according to claim 1, wherein the ketone is one memberselected from the group consisting of acetone, methylethylketone,methyl-i-butylketone, acetophenone and benzophenone.

6. A process according to claim 1, wherein the hydrocarbon andhalogenated hydrocarbon is one member selected from the group consistingof pentane, n-hexane, cyclohexane, chloroform, carbon tetrachloride,dichloroethane, trichloroethane, dichloroethylene, trichloroethylene,benzene, toluene, xylene, monochlorobenzene and dichlorobenzene.

7. A process according to claim 1, wherein the alkaline phosphate is onemember selected from the group consisting of sodium orthophosphate,potassium orthophosphate, sodium pyrophosphate, potassium pyrophosphate,sodium tripolyphosphate and potassium tripolyphoshate; alkaliphosphaates; and aqueous solutions of orthophosphoric acid,metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, sodiumprimary phosphate, potassium primary phosphate, sodium secondaryphosphate, potassium secondary phosphate, sodium metaphosphate andpotassium metaphosphate which have been made alkaline by addition of analkaline substance.

8. A process according to claim 1, wherein the alkaline silicate is onemember selected from the group consisting of sodium silicate, potassiumsilicate, sodium tetrasilicate, potassium tetrasilicate, sodiummetasilicate, potassium metasilicate and a mixture thereof; and aqueoussolutions of silicon monoxide, silicic acid, tetrasilicic acid and metasilicic acid which have been made alkaline by addition of an alkalinesubstance.

9. An optical brightening composition consisting essentially of fl-formcrystals of a compound represented by the formula 1 1 wherein Rlishydrogen atom or methyl group; and M is sodium or potassium, and atleast one of alkaline phosphates and/or alkaline silicates, the amountratio of said Si-form crystals and said phosphate and/ or silicatesbeing 1:01 to 10.

10. A composition according to claim 9, wherein the alkaline phosphateis one member selected from the group consisting of sodiumorthophosphate, potassium orthophosphate, sodium pyrophosphate,potassium pyrophosphate, sodium tripolyphosphate and potassiumtripolyphosphate, and alkali phosphates.

11. A composition according to claim 9, wherein the alkaline phosphateis one member selected from the group consisting of aqueous solutions oforthophosphoric acid, metaphosphoric acid, pyrophosphoric acid,tripolyphosphoric acid, sodium primary phosphate, potassium primaryphosphate, sodium secondary phosphate, potassium secondary phosphate,sodium metaphosphate and potassium metaphosphate which have been madealkaline by addition of an alkaline substance.

12. A composition according to claim 9, wherein the alkaline silicate isone member selected from the group consisting of sodium silicate,potassium silicate, sodium tetrasilicate, potassium tetrasilicate,sodium metasilicate, potassium metasilicate and a mixture thereof.

1 13. A composition according to claim 9, wherein the alkaline silicateis one member selected from the group consisting of aqueous solutions ofsilicon monoxide, silicic acid, tetrasilicic acid and metasilicic acidwhich have been made alkaline by addition of an alkaline substance.

14. An optical brightening composiition comprising an aqueous dispersionor an aqueous suspension of fl-form crystals of a compound representedby the formula UNITED STATES PATENTS 2,986,528 5/1961 Siegrist et al.252301.2 3,012,971 12/1961 Gessner et al. 252301.2 3,132,106 5/1964Villaume 252--301.2 3,467,600 9/ 1969 Zweidler et al 252-301.2 3,472,84210/ 1969 Hausermann et al. 260240 FOREIGN PATENTS 680,847 11/ 1966Belgium.

TOBIAS E. LEVOW, Primary Examiner A. P. DEMERS, Assistant Examiner US.Cl. X.R.

UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTIQN Patent No.3,630,944 Dated December 28, 1971 Inventor(s) Masaaki Ohkawa et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below} Column 1,line 12: change priority claim B/23,619" to read --43/23,6lO-.

Signed and sealed this 25th day of July .1972.

(SEAL) Attest:

EDWARD M.FLETcm.-R,JR. ROBERT GOT'ISCHALK Attesting'Officer Commissionerof Patents FORM po'wso 0&9, USCOMM-DC suave-p69 US GOVERNMENT PRINTINGOFFICE: I969 O-366-334

